Method rcv_settings_frame

src/proxy/http2/Http2ConnectionState.cc:700–814

}

Http2Error
Http2ConnectionState::rcv_settings_frame(const Http2Frame &frame)
{
  Http2SettingsParameter param;
  char                   buf[HTTP2_SETTINGS_PARAMETER_LEN];
  unsigned               nbytes    = 0;
  const Http2StreamId    stream_id = frame.header().streamid;

  Http2StreamDebug(this->session, stream_id, "Received SETTINGS frame");

  if (this->get_zombie_event()) {
    Warning("Setting frame for zombied session %" PRId64, this->session->get_connection_id());
  }

  // Update SETTINGS frame count per minute
  this->increment_received_settings_frame_count();
  // Close this connection if its SETTINGS frame count exceeds a limit
  if (configured_max_settings_frames_per_minute >= 0 &&
      this->get_received_settings_frame_count() > static_cast<uint32_t>(configured_max_settings_frames_per_minute)) {
    Metrics::Counter::increment(http2_rsb.max_settings_frames_per_minute_exceeded);
    Http2StreamDebug(this->session, stream_id, "Observed too frequent SETTINGS frames: %u frames within a last minute",
                     this->get_received_settings_frame_count());
    return Http2Error(Http2ErrorClass::HTTP2_ERROR_CLASS_CONNECTION, Http2ErrorCode::HTTP2_ERROR_ENHANCE_YOUR_CALM,
                      "recv settings too frequent SETTINGS frames");
  }

  // [RFC 7540] 6.5. The stream identifier for a SETTINGS frame MUST be zero.
  // If an endpoint receives a SETTINGS frame whose stream identifier field is
  // anything other than 0x0, the endpoint MUST respond with a connection
  // error (Section 5.4.1) of type PROTOCOL_ERROR.
  if (stream_id != 0) {
    return Http2Error(Http2ErrorClass::HTTP2_ERROR_CLASS_CONNECTION, Http2ErrorCode::HTTP2_ERROR_PROTOCOL_ERROR,
                      "recv settings stream not 0");
  }

  // [RFC 7540] 6.5. Receipt of a SETTINGS frame with the ACK flag set and a
  // length field value other than 0 MUST be treated as a connection
  // error of type FRAME_SIZE_ERROR.
  if (frame.header().flags & HTTP2_FLAGS_SETTINGS_ACK) {
    if (frame.header().length == 0) {
      this->_process_incoming_settings_ack_frame();
      return Http2Error(Http2ErrorClass::HTTP2_ERROR_CLASS_NONE);
    } else {
      return Http2Error(Http2ErrorClass::HTTP2_ERROR_CLASS_CONNECTION, Http2ErrorCode::HTTP2_ERROR_FRAME_SIZE_ERROR,
                        "recv settings ACK header length not 0");
    }
  }

  // A SETTINGS frame with a length other than a multiple of 6 octets MUST
  // be treated as a connection error (Section 5.4.1) of type
  // FRAME_SIZE_ERROR.
  if (frame.header().length % 6 != 0) {
    return Http2Error(Http2ErrorClass::HTTP2_ERROR_CLASS_CONNECTION, Http2ErrorCode::HTTP2_ERROR_FRAME_SIZE_ERROR,
                      "recv settings header wrong length");
  }

  uint32_t n_settings = 0;
  while (nbytes < frame.header().length) {